When I offer to do something, it means I want to do it. And if someone asks me to do something, it means they want me to do it and whether or not they get what they want is contingent upon my decision and desire to do it. So, say, theoretically someone asks me to do something and I comply. Then I'm asked to do it again and my desire to please the other person lessens, but I comply again. Finally, the third time I am looked to as a convenient solution to a problem in which another person is solely responsible for, I'm not asked, I am told to comply. And usually by this time I'm annoyed and prepared to tell the other person NO. I'm left to do whatever it is that the person wants me to do with virtually no choice. That's when being a little annoyed turns into being completely enraged. This is called taking advantage. According to google, to "take advantage" has two definitions. They are:
 

You cannot assume that because a person has always been there for you that they always will, or always want to be. Don't get me wrong; I'm not a selfish person by any means, but quite frankly I'm sick of everyone else gaining from my selfless services. Sure, sometimes I get reimbursed for what I do for people, but I'd rather be broke than someone's Johnny on the spot.

To all those people who freely and guiltlessly take advantage of others...

WHAT THE VUCK?! VUCK YOU!